/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.googlecode.bluetools.dom4j;

import com.googlecode.bluetools.dom4j.tree.AbstractNode;
import com.googlecode.bluetools.dom4j.tree.DefaultNamespace;
import com.googlecode.bluetools.dom4j.tree.NamespaceCache;

/**
 * <p>
 * <code>Namespace</code> is a Flyweight Namespace that can be shared amongst nodes.
 * </p>
 * 
 * @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
 * @version $Revision: 1.1 $
 */
public class Namespace extends AbstractNode {
	/** Cache of Namespace instances */
	protected static final NamespaceCache CACHE = new NamespaceCache();

	/** XML Namespace */
	public static final Namespace XML_NAMESPACE = CACHE.get("xml", "http://www.w3.org/XML/1998/namespace");

	/** No Namespace present */
	public static final Namespace NO_NAMESPACE = CACHE.get("", "");

	/** The prefix mapped to this namespace */
	private String prefix;

	/** The URI for this namespace */
	private String uri;

	/** A cached version of the hashcode for efficiency */
	private int hashCode;

	/**
	 * DOCUMENT ME!
	 * 
	 * @param prefix is the prefix for this namespace
	 * @param uri is the URI for this namespace
	 */
	public Namespace(String prefix, String uri) {
		this.prefix = (prefix != null) ? prefix : "";
		this.uri = (uri != null) ? uri : "";
	}

	/**
	 * A helper method to return the Namespace instance for the given prefix and URI
	 * 
	 * @param prefix DOCUMENT ME!
	 * @param uri DOCUMENT ME!
	 * 
	 * @return an interned Namespace object
	 */
	public static Namespace get(String prefix, String uri) {
		return CACHE.get(prefix, uri);
	}

	/**
	 * A helper method to return the Namespace instance for no prefix and the URI
	 * 
	 * @param uri DOCUMENT ME!
	 * 
	 * @return an interned Namespace object
	 */
	public static Namespace get(String uri) {
		return CACHE.get(uri);
	}

	public short getNodeType() {
		return NAMESPACE_NODE;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the hash code based on the qualified name and the URI of the namespace.
	 */
	public int hashCode() {
		if (hashCode == 0) {
			hashCode = createHashCode();
		}

		return hashCode;
	}

	/**
	 * Factory method to create the hashcode allowing derived classes to change the behaviour
	 * 
	 * @return DOCUMENT ME!
	 */
	protected int createHashCode() {
		int result = uri.hashCode() ^ prefix.hashCode();

		if (result == 0) {
			result = 0xbabe;
		}

		return result;
	}

	/**
	 * Checks whether this Namespace equals the given Namespace. Two Namespaces are equals if their URI and prefix are
	 * equal.
	 * 
	 * @param object DOCUMENT ME!
	 * 
	 * @return DOCUMENT ME!
	 */
	public boolean equals(Object object) {
		if (this == object) {
			return true;
		}
		else if (object instanceof Namespace) {
			Namespace that = (Namespace) object;

			// we cache hash codes so this should be quick
			if (hashCode() == that.hashCode()) {
				return uri.equals(that.getURI()) && prefix.equals(that.getPrefix());
			}
		}

		return false;
	}

	public String getText() {
		return uri;
	}

	public String getStringValue() {
		return uri;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the prefix for this <code>Namespace</code>.
	 */
	public String getPrefix() {
		return prefix;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @return the URI for this <code>Namespace</code>.
	 */
	public String getURI() {
		return uri;
	}

	public String getXPathNameStep() {
		if ((prefix != null) && !"".equals(prefix)) {
			return "namespace::" + prefix;
		}

		return "namespace::*[name()='']";
	}

	public String getPath(Element context) {
		StringBuffer path = new StringBuffer(10);
		Element parent = getParent();

		if ((parent != null) && (parent != context)) {
			path.append(parent.getPath(context));
			path.append('/');
		}

		path.append(getXPathNameStep());

		return path.toString();
	}

	public String getUniquePath(Element context) {
		StringBuffer path = new StringBuffer(10);
		Element parent = getParent();

		if ((parent != null) && (parent != context)) {
			path.append(parent.getUniquePath(context));
			path.append('/');
		}

		path.append(getXPathNameStep());

		return path.toString();
	}

	public String toString() {
		return super.toString() + " [Namespace: prefix " + getPrefix() + " mapped to URI \"" + getURI() + "\"]";
	}

	public String asXML() {
		StringBuffer asxml = new StringBuffer(10);
		String pref = getPrefix();

		if ((pref != null) && (pref.length() > 0)) {
			asxml.append("xmlns:");
			asxml.append(pref);
			asxml.append("=\"");
		}
		else {
			asxml.append("xmlns=\"");
		}

		asxml.append(getURI());
		asxml.append("\"");

		return asxml.toString();
	}

	public void accept(Visitor visitor) {
		visitor.visit(this);
	}

	protected Node createXPathResult(Element parent) {
		return new DefaultNamespace(parent, getPrefix(), getURI());
	}
}

/*
 * Redistribution and use of this software and associated documentation ("Software"), with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions must also contain a
 * copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived from this Software without prior written
 * permission of MetaStuff, Ltd. For written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may "DOM4J" appear in their names without prior
 * written permission of MetaStuff, Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
